Abstract
Omphalomesenteric cysts are an exceedingly rare type of embryologic remnant of the omphalomesenteric duct. Owing to its rarity and unspecific imaging findings, it is occasionally difficult to diagnose preoperatively. Herein, we report the case of a 15-month-old female with an omphalomesenteric cyst that presented as a painful abdominal mass. Imaging showed a 4 cm cystic lesion just beneath the umbilicus, which also contained a 1 cm enhanced lesion. On the immediate right side of this cyst, a 7 cm hematoma was found within the abdominal wall. Aspiration revealed bloody fluid with an amylase level of 38,250 U/L. She was then diagnosed with an omphalomesenteric cyst, with aberrant pancreas and associated hematoma of the abdominal wall. These findings were confirmed with laparotomy and subsequent pathological examinations. The high level of amylase in the cyst led us to speculate the existence of ectopic pancreatic tissue. Thus, amylase measurement may be considered for the diagnosis of an omphalomesenteric cyst.